System and method for charging plug-in hybrid vehicle

ABSTRACT

A system and method for charging a plug-in hybrid vehicle can improve the on-board charging efficiency of the plug-in hybrid vehicle by adjusting a frequency of operation of a cooler when cooling an on-board charger (OBC) by circulating coolant when the temperature of the OBC rises while a high-voltage battery is being charged. The operations of a water pump and a radiator fan are controlled by determining whether the voltage of the high-voltage battery is within or out of a reference voltage range in which the on-board charging of the high-voltage battery is performed. This consequently prevents power from being unnecessarily consumed by operation of the cooler, such that the efficiency of charging is improved and the OBC is properly cooled.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims under 35 U.S.C. §119(a) the benefit ofKorean Patent Application No. 10-2016-0065078, filed May 26, 2016, theentire contents of which are incorporated by reference herein.

BACKGROUND 1. Technical Field

The present invention relates generally to a system and method forcharging a plug-in hybrid vehicle, the system and method beingconfigured to improve the on-board charging efficiency of a plug-inhybrid vehicle.

2. Description of the Related Art

An on-board charger (OBC) is disposed in a vehicle such as an electricvehicle or a plug-in hybrid vehicle using electricity as a main powersource to charge a battery of the vehicle using 110V or 220Velectricity.

The OBC generates a large amount of heat while charging the battery ofthe vehicle with electricity. Such heat may have a significant adverseeffect on the lifespan of the battery as well as the performance andlifespan of the OBC unless controlled. Thus, coolant is supplied to theOBC to control heat generated during charging to ensure that thetemperature of the OBC is within a predetermined range.

When the temperature of the OBC rises during the charging of the batteryas described above, the coolant is circulated to cool the OBC. Thecoolant is circulated as the temperature of the OBC rises shortly afterthe start of charging of the battery. When the temperature of the OBCrises, a cooling system circulates an excessive amount of coolant towardthe OBC. Thus, power consumed by the cooling system lowers theefficiency of charging.

In the related art, during the charging of the battery, the cooling ofthe OBC is performed considering the efficiency of charging asinfluenced by the cooling of the OBC, thereby inefficiently consumingpower. Thus, there are demands for minimizing the amount of powerconsumed by the operation of the cooling system.

The foregoing is intended merely to aid in the understanding of thebackground of the present invention, and is not intended to mean thatthe present invention falls within the purview of the related art thatis already known to those skilled in the art.

SUMMARY

Accordingly, the present invention provides a system and method forcharging a plug-in hybrid vehicle, the charging system and method beingconfigured to improve the on-board charging efficiency of a plug-inhybrid vehicle by adjusting the frequency of operation of a cooler whencooling an on-board charger (OBC) by circulating coolant when thetemperature of the OBC rises while a battery is being charged.

In order to achieve the above object, according to one aspect of thepresent invention, a system for charging a plug-in hybrid vehicle mayinclude: a cooler configured to cool an OBC by circulating coolanttherethrough, the OBC charging a high-voltage battery of a vehicle; anda controller having voltage information of the high-voltage batteryinput thereto and a reference voltage range previously stored therein,wherein when a voltage of the high-voltage battery is within thereference voltage range, the controller decreases a frequency ofoperation and an intensity of cooling of the cooler, and when thevoltage of the high-voltage battery is out of the reference voltagerange, the controller increases the frequency of operation and theintensity of cooling of the cooler.

The cooler may include a water pump configured to cause a cooling mediumto circulate when the OBC is required to be cooled.

When the voltage of the high-voltage battery is lower than the referencevoltage range, the controller may control the water pump to operate whena temperature of the OBC has reached an operating temperature range thatis previously-stored.

When the voltage of the high-voltage battery is within the referencevoltage range, the controller may control the water pump to operate in acorrected temperature range higher than the operating temperature range.

When the voltage of the high-voltage battery is lower than the referencevoltage range, the controller may control the water pump to operate atan operating speed that is previously stored.

When the voltage of the high-voltage battery is within the referencevoltage range, the controller may control the water pump to operate in acorrected temperature range lower than the operating temperature range.

The cooler may include a radiator fan configured to adjust a temperatureof a cooling medium that circulates to cool the OBC.

When the voltage of the high-voltage battery is lower than the referencevoltage range, the controller may control the radiator fan to operatewhen a temperature of the OBC has reached an operating temperature rangethat is previously stored.

When the voltage of the high-voltage battery is within the referencevoltage range, the controller may control the radiator fan to operate ina corrected temperature range higher than the operating temperaturerange.

The controller may control the radiator fan to operate at a higherintensity of operation with increases in temperature in the operatingtemperature range or the corrected temperature range.

According to one aspect of the present invention, a method of charging aplug-in vehicle may include: measuring, by a controller, a voltage of ahigh-voltage battery; increasing, by the controller, a frequency ofoperation and an intensity of cooling of a cooler when the voltage ofthe high-voltage battery is out of a reference voltage range that ispreviously stored after measuring the voltage of the high-voltagebattery; and reducing, by the controller, the frequency of operation andthe intensity of cooling of the cooler when the voltage of thehigh-voltage battery is within the reference voltage range that ispreviously stored after measuring the voltage of the high-voltagebattery.

The cooler may include a water pump configured to cause a cooling mediumto circulate when an OBC is required to be cooled and a radiator fanconfigured to adjust a temperature of the cooling medium that circulatesto cool the OBC. In the step of increasing the frequency of operationand the intensity of cooling and reducing the frequency of operation andthe intensity of cooling, an operating temperature range and anintensity of operation of the water pump and the radiator fan may varydepending on the voltage of the high-voltage battery.

In the step of increasing the frequency of operation and the intensityof cooling, when the voltage of the high-voltage battery is lower thanthe reference voltage range, the water pump may be controlled to operateat an operating speed that is previously stored when a temperature ofthe OBC has reached the operating speed.

In the step of reducing the frequency of operation and the intensity ofcooling, when the voltage of the high-voltage battery is within thereference voltage range, the water pump may be controlled to operate ina corrected temperature range higher than the operating temperaturerange when a temperature of the OBC has reached the operating speed.

In the step of increasing the frequency of operation and the intensityof cooling, when the voltage of the high-voltage battery is lower thanthe reference voltage range, the radiator fan may be controlled tooperate when a temperature of the OBC has reached the operatingtemperature range.

In the step of reducing the frequency of operation and the intensity ofcooling, when the voltage of the high-voltage battery is within thereference voltage range, the radiator fan may be controlled to operatein a corrected temperature range higher than the operating temperaturerange.

A non-transitory computer readable medium containing programinstructions executed by a processor includes: program instructions thatmeasure a voltage of a high-voltage battery; program instructions thatincrease a frequency of operation and an intensity of cooling of acooler when the voltage of the high-voltage battery is out of areference voltage range that is previously stored after measuring thevoltage of the high-voltage battery; and program instructions thatreduce the frequency of operation and the intensity of cooling of thecooler when the voltage of the high-voltage battery is within thereference voltage range that is previously stored after measuring thevoltage of the high-voltage battery.

According to the system and method for charging a plug-in hybrid vehicleas described above, it is possible to improve the on-board chargingefficiency of a plug-in hybrid vehicle by adjusting the frequency ofoperation of a cooler when cooling an OBC by circulating coolant whenthe temperature of the OBC rises while a battery is being charged.

The operation of the water pump and the operation of the radiator fanare controlled by determining whether the voltage of the high-voltagebattery is within or out of a reference voltage range in which thehigh-voltage battery is charged using the OBC. This prevents power frombeing unnecessarily consumed by the operation of the cooler, therebyimproving the efficiency of charging and facilitating the cooling of theOBC.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a block diagram of a configuration of a system for charging aplug-in hybrid vehicle according to an exemplary embodiment of thepresent invention;

FIGS. 2 to 5 are graphs of the system for charging the plug-in hybridvehicle shown in FIG. 1;

FIG. 6 is a flowchart of a method of charging the plug-in hybrid vehicleaccording to an exemplary embodiment of the present invention; and

FIGS. 7 and 8 are flowcharts of the method of charging the plug-inhybrid vehicle shown in FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

It is understood that the term “vehicle” or “vehicular” or other similarterm as used herein is inclusive of motor vehicles in general such aspassenger automobiles including sports utility vehicles (SUV), buses,trucks, various commercial vehicles, watercraft including a variety ofboats and ships, aircraft, and the like, and includes hybrid vehicles,electric vehicles, plug-in hybrid electric vehicles, hydrogen-poweredvehicles and other alternative fuel vehicles (e.g. fuels derived fromresources other than petroleum). As referred to herein, a hybrid vehicleis a vehicle that has two or more sources of power, for example bothgasoline-powered and electric-powered vehicles.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. Throughout the specification, unless explicitly describedto the contrary, the word “comprise” and variations such as “comprises”or “comprising” will be understood to imply the inclusion of statedelements but not the exclusion of any other elements. In addition, theterms “unit”, “-er”, “-or”, and “module” described in the specificationmean units for processing at least one function and operation, and canbe implemented by hardware components or software components andcombinations thereof.

Further, the control logic of the present invention may be embodied asnon-transitory computer readable media on a computer readable mediumcontaining executable program instructions executed by a processor,controller or the like. Examples of computer readable media include, butare not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes,floppy disks, flash drives, smart cards and optical data storagedevices. The computer readable medium can also be distributed in networkcoupled computer systems so that the computer readable media is storedand executed in a distributed fashion, e.g., by a telematics server or aController Area Network (CAN).

Hereinafter, a system and method for charging a plug-in hybrid vehicleaccording to exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.Throughout the drawings, the same reference numerals will refer to thesame or like parts.

FIG. 1 is a block diagram of a configuration of a system for charging aplug-in hybrid vehicle according to an exemplary embodiment of thepresent invention, FIGS. 2 to 5 are graphs of the system for chargingthe plug-in hybrid vehicle shown in FIG. 1, FIG. 6 is a flowchart of amethod of charging the plug-in hybrid vehicle according to an exemplaryembodiment of the present invention, and FIGS. 7 and 8 are flowcharts ofthe method of charging the plug-in hybrid vehicle shown in FIG. 6.

As shown in FIG. 1, the charging system for a vehicle such as a plug-inhybrid vehicle according to the present invention includes: a cooler 300and a controller 400. The cooler 300 cools an on-board charger (OBC) 200by circulating coolant therethrough, the OBC 200 configured to charge ahigh-voltage battery 100 of the vehicle. The controller 400 has thevoltage information of the high-voltage battery 100 input thereto and areference voltage range previously stored therein. When the voltage ofthe high-voltage battery 100 is within the reference voltage range, thecontroller 400 decreases the frequency of operation and the intensity ofcooling of the cooler 300. When the voltage of the high-voltage battery100 is out of the reference voltage range, the controller 400 increasesthe frequency of operation and the intensity of cooling of the cooler300.

The present invention is intended to improve the on-board chargingefficiency of a plug-in hybrid vehicle. The frequency of operation andthe intensity of cooling of the cooler 300, operating during thecharging of the high-voltage battery 100, are adjusted depending on thevoltage of the high-voltage battery 100 to improve the efficiency of thecharging.

The high-voltage battery 100 is a battery used in an electric vehicle ora hybrid vehicle to store high capacity electric energy. The OBC 200serves to generate a buffer voltage at a lowest voltage requested by thehigh-voltage battery 100 and supply the buffer voltage as charging powerwhen high-voltage battery 100 is charged with electric energy. A voltageable to be output by the high-voltage battery 100 is determineddepending on the initial design. This voltage is influenced by a stateof charge (SOC) and the temperature of the high-voltage battery 100.That is, when the SOC of the high-voltage battery 100 is lower, thevoltage able to be normally output may be lower. In contrast, when theSOC of the high-voltage battery 100 is higher, the voltage able to benormally output may be higher. The voltage able to be normally outputvaries depending on the amount of heat generated by the high-voltagebattery 100 and the ambient temperature.

The cooler 300 serves to cool electronic parts of the battery system ofthe high-voltage battery 100 including the OBC 200. The cooler 300 cancool the OBC 200 using, typically, coolant. In response to thehigh-voltage battery 100 being charged, the cooler 300 operates to coolthe OBC 200. When the cooler 300 operates to cool only the OBC 200 inthe same manner as cooling the battery system, an unnecessary amount ofpower is consumed. Thus, according to the present invention, theoperation of the cooler 300 is variably controlled depending on thevoltage information of the high-voltage battery 100 to minimize theamount of power consumed by the operation of the cooler 300.

In this regard, the controller 400 has the voltage information of thehigh-voltage battery 100 input thereto, and has the reference voltagerange previously stored therein. When the voltage of the high-voltagebattery 100 is within the reference voltage range, the controller 400increases the frequency of operation and the intensity of cooling of thecooler 300. When the voltage of the high-voltage battery 100 is out ofthe reference voltage range, the controller 400 decreases the frequencyof operation and the intensity of cooling of the cooler 300. The voltageinformation of the high-voltage battery 100 may be obtained by measuringvoltages output by the cells of high-voltage battery 100 or by measuringvoltages of the high-voltage battery 100 by reading voltages of acapacitor during switching on/off of a relay in the circuit of thehigh-voltage battery 100. In addition, the voltage information may beobtained by measuring voltages of the high-voltage battery 100 by avariety of other methods.

The reference voltage range stored in the controller 400 is a range ofvoltage with which the high-voltage battery 100 is actually charged. Ingeneral, the reference voltage range is a range in which a low voltageis output due to insufficient capacity of the high-voltage battery 100or a range in which the high-voltage battery 100 is completely charged.That is, when the high-voltage battery 100 has obtained a considerableamount of power capacity, a normal voltage is output. Then, during thecharging, the amount of heat generated by the OBC 200 is not increased.In contrast, when the capacity of the high-voltage battery 100 is lower,the voltage able to be output is lowered and a necessary amount ofcharging is also increased, thereby increasing the amount of heatgenerated by the OBC 200. Thus, the frequency of operation and theintensity of cooling of the cooler 300 must be increased.

Thus, according to the present invention, a voltage output by thehigh-voltage battery 100 is measured, and the operation of the cooler300 is controlled in dual modes depending on the voltage output by thehigh-voltage battery 100 in consideration of the amount of heatgenerated by the OBC 200 during the charging. Consequently, thetemperature of the OBC 200 is adjusted, and power consumed by theoperation of the cooler 300 during the charging is minimized, therebyimproving the efficiency of charging.

The above-described features of the present invention will be describedin detail as follows. The cooler 300 includes a water pump 320configured to cause a cooling medium to circulate when the OBC 200 isrequired to be cooled, and a radiator fan 320 configured to adjust thetemperature of the cooling medium that circulates to cool the OBC 200.The water pump 320 may be an electronic water pump.

First, a description will be given of control over the water pump 320.When the voltage of the high-voltage battery 100 is lower than thereference voltage range, the controller 400 controls the water pump 320to operate when the temperature of the OBC 200 has reached apreviously-stored operating temperature range. Here, the temperature ofthe OBC 200 can be measured using a temperature sensor 202.

In contrast, when the voltage of the high-voltage battery 100 is withinthe reference voltage range, the controller 400 controls the water pump320 to operate in a corrected temperature range higher than theoperating temperature range.

Here, when the voltage of the high-voltage battery 100 is lower than thereference voltage range, an output voltage is lowered due to a smallcapacity of the high-voltage battery 100, such that a greater amount ofelectricity must be charged, thereby increasing the amount of heatgenerated by the OBC 200 during the charging of the high-voltage battery100. Thus, the operating temperature range is set to increase thefrequency of operation of the cooler 300. That is, since the operatingtemperature range of the OBC 200 in which the OBC 200 continuously orrepeatedly operates during the charging of the high-voltage battery 100is set to a low temperature range, the frequency of operation of thewater pump 320 can be increased, thereby continuously cooling the OBC200 that generates heat during the charging.

In this state, when the high-voltage battery 100 is charged to apredetermined level, the temperature at which the OBC 200 generates heatgenerated is lowered due to the charging characteristics of the battery.Thus, when the voltage of the high-voltage battery 100 is within thereference voltage range, the controller 400 decreases the frequency ofthe operation of the water pump 320 by causing the water pump 320 tooperate in the corrected temperature range that is higher than theoperating temperature range. That is, since the corrected temperaturerange is corrected to be higher than the operating temperature range,the water pump 320 operates when the temperature of the OBC 200 hasreached the higher corrected temperature range, thereby decreasing thefrequency of the operation of the water pump 320. In addition, when thevoltage of the high-voltage battery 100 is within the reference voltagerange, the controller 400 causes the water pump 320 to operate in thecorrected temperature range. This can consequently minimize the amountof power consumed by the water pump 320 unnecessarily continuouslyoperating, thereby improving the efficiency of charging.

In addition, when the voltage of the high-voltage battery 100 is lowerthan the reference voltage range, the controller 400 controls the waterpump 320 to operate at a previously-stored operating speed.

Furthermore, when the voltage of the high-voltage battery 100 is withinthe reference voltage range, the controller 400 controls the water pump320 to operate at a corrected speed slower than the operating speed.

Here, when the voltage of the high-voltage battery 100 is lower than thereference voltage range, the high-voltage battery 100 is charged with alarger amount of electricity, thereby increasing the amount of heatgenerated by the OBC 200. Thus, the cooling speed of the water pump 320must be increased. Consequently, the controller 400 increases theintensity of the operation of the water pump 320, such that the waterpump 320 operates at higher revolutions per minute (rpm), therebyensuring that a greater amount of cooling medium circulates to the OBC200.

In this state, when the high-voltage battery 100 is charged in asuitable level, the temperature at which the OBC 200 generates heat islowered. Thus, when the voltage of the high-voltage battery 100 iswithin the reference voltage range, the controller 400 controls thewater pump 320 to operate at a corrected speed slower than the operatingspeed, thereby decreasing the cooling speed. That is, the correctedspeed is a command value by which the water pump 320 operates at aslower speed than the operating speed. The controller 400 causes thewater pump 320 to operate at the corrected speed when the voltage of thehigh-voltage battery 100 is within the reference voltage range. Thisconsequently reduces the amount of power consumed due to the excessiveoperation of the water pump 320, thereby improving the efficiency ofcharging.

Hereinafter, an exemplary operation of the water pump 320 will bedescribed with reference to the drawings. When the voltage of thehigh-voltage battery 100 has not reached the reference voltage range,the controller 400 causes the water pump 320 to operate at 2500 rpm,i.e. the operating speed in a previously-stored operating temperaturerange of 36° C. to 40° C. When the voltage of the high-voltage battery100 has not reached the reference voltage range as described above, thefrequency of operation of the water pump 320 is increased by causing thewater pump 320 to continuously operate in a lower temperature range andthe intensity of operation of the water pump 320 is increased, such thatcooling can be performed sufficiently when the OBC 200 generates heat.

When the voltage of the high-voltage battery 100 has reached thereference voltage range in this state, the water pump 320 is caused tooperate at a corrected speed of 1500 rpm in a previously-storedcorrected temperature range of 56° C. to 60° C., as shown in FIG. 3.When the voltage of the high-voltage battery 100 has reached thereference voltage range, the frequency of operation of the water pump320 is reduced by causing the water pump 320 to operate in a highertemperature range and the intensity of operation of the water pump 320is reduced, such that the OBC 200 is excessively cooled.

This consequently prevents power from being unnecessarily consumed bythe operation of the cooler 300 and facilitates the cooling of the OBC200.

Hereinafter, a description will be given of control over the radiatorfan 340. When the voltage of the high-voltage battery 100 is lower thanthe reference voltage range, the controller 400 controls the radiatorfan 340 to operate when the temperature of the OBC 200 has reached apreviously-stored operating temperature range.

In contrast, when the voltage of the high-voltage battery 100 is withinthe reference voltage range, the controller 400 controls the radiatorfan 340 to operate in a corrected temperature range higher than theoperating temperature range.

The operating temperature range is a temperature range set to increasethe frequency of operation of the radiator fan 340, since the amount ofheat generated by the OBC 200 increases during the charging of thehigh-voltage battery 100 when the voltage of the high-voltage battery100 is lower than the reference voltage range. Specifically, while thehigh-voltage battery 100 is being charged, the radiator fan 340continuously operates in the operating temperature range of the OBC 200that is set to be a lower temperature range. The frequency of operationof the radiator fan 340 is increased to lower the temperature of thecooling medium, such that the OBC 200 that generates heat during thecharging can be efficiently performed.

In this state, when the high-voltage battery 100 is charged to asuitable level, the temperature of heat generated by the OBC 200 islowered. Thus, when the voltage of the high-voltage battery 100 iswithin the reference voltage range, the controller 400 controls theradiator fan 340 to operate in a corrected temperature range higher thanthe operating temperature range, thereby lowering the frequency ofoperation of the radiator fan 340.

Specifically, the corrected temperature range is higher than theoperating temperature range. Since the radiator fan 340 operates whenthe temperature of the OBC 200 has reached the corrected temperaturerange higher than the operating temperature range, the frequency ofoperation of the radiator fan 340 is reduced. Thus, when the voltage ofthe high-voltage battery 100 is within the reference voltage range, thecontroller 400 controls the radiator fan 340 to operate in the correctedtemperature range. This consequently minimizes the amount of powerconsumed by unnecessary continuous operation of the radiator fan 340,thereby improving the efficiency of charging.

In addition, as the temperature rises in the operating temperature rangeand the corrected temperature range, the controller 400 controls theintensity of operation of the radiator fan 340 to be increased.

As described above, the controller 400 variably controls the intensityof operation of the radiator fan 340 depending on the temperature of theOBC 200, such that the temperature of the cooling medium is efficientlyadjusted depending on the temperature of the OBC 200. Specifically, in alow temperature range in which the temperature of the OBC 200 is preset,the radiator fan 340 is controlled to operate at a previously-set lowlevel. In a temperature range in which the temperature of the OBC 200 ishigher, the radiator fan 340 is controlled to operate at a higher level.In this manner, the temperature of the cooling medium is adjusteddepending on the temperature of the OBC 200, such that the cooling ofthe OBC 200 is efficiently performed.

Hereinafter, a description will be given of an exemplary operation ofthe radiator fan 340 with reference to the accompanying drawings. Whenthe voltage of the high-voltage battery 100 has not reached thereference voltage range, the controller 400 controls the radiator fan340 to operate in a previously-stored operating temperature range of 41°C. to 50° C., as shown in FIG. 4. When the temperature of the OBC 200 isin a range of 41° C. to 45° C., the radiator fan 340 is controlled tooperate at a lower power level. When the temperature of the OBC 200 isin a range of 46° C. to 50° C., the radiator fan 340 may be controlledto operate at a higher power level.

As described above, when the voltage of the high-voltage battery 100 hasnot reached the reference voltage range, the radiator fan 340 iscontrolled to continuously operate in a low temperature range toincrease the frequency of operation. This consequently lowers thetemperature of the cooling medium, whereby the OBC 200 is sufficientlycooled.

In this state, when the voltage of the high-voltage battery 100 hasreached the reference voltage range, the radiator fan 340 is controlledto operate in a previously-stored temperature range of 60° C. to 70° C.,as shown in FIG. 5. As described above, the frequency of operation ofthe radiator fan 340 is reduced when the voltage of the high-voltagebattery 100 has reached the reference voltage range. This consequentlyprevents power from being unnecessarily consumed by the excessiveoperation of the radiator fan 340, thereby improving the efficiency ofcharging.

As shown in FIG. 6, a method of charging a plug-in hybrid vehicleincludes: a measuring step S100 of measuring the voltage of ahigh-voltage battery; a rapid cooling step S200 of increasing thefrequency of operation and the intensity of cooling of the cooler 300when the voltage of the high-voltage battery is out of apreviously-stored reference voltage range after the measuring step S100;and a safe cooling step S300 of reducing the frequency of operation andthe intensity of cooling of the cooler 300 when the voltage of thehigh-voltage battery is within the previously-stored reference voltagerange after the measuring step S100.

The voltage of the high-voltage battery is measured at the measuringstep S100 as described above, and a step S101 of comparing the voltageof the high-voltage battery with the previously-stored reference voltagerange is performed. Afterwards, when the voltage of the high-voltagebattery is out of the previously-stored reference voltage range, therapid cooling step S200 is performed. When the voltage of thehigh-voltage battery is within the previously-stored reference voltagerange, the safe cooling step S300 is performed.

Specifically, the cooler 300 includes the water pump 320 configured tocause a cooling medium to circulate when the OBC 200 is required to becooled and the radiator fan 320 configured to adjust the temperature ofthe cooling medium that circulates to cool the OBC 200. The rapidcooling step S200 and the safe cooling step S300 are performed such thatthe operating temperature ranges of the water pump 320 and the radiatorfan 340 and the intensities of operation can vary.

In the rapid cooling step S200, when the voltage of the high-voltagebattery is lower than the reference voltage range, a step S202 ofdetermining whether or not the temperature of the OBC 200 has reached anoperating temperature range set to be lower than a corrected temperaturerange to be described later is performed. Afterwards, when thetemperature of the OBC 200 has reached the previously-stored operatingtemperature range, a step S204 of controlling the water pump 320 tooperate at a previously-stored operating speed is performed. Here, theoperating speed is set such that the water pump 320 operates at amaximum power level. When the voltage of the high-voltage battery islower than the reference voltage range, the operating speed is increasedtogether with the frequency of operation of the water pump 320, suchthat the OBC 200 is sufficiently cooled.

In the safe cooling step S300, when the voltage of the high-voltagebattery is within the reference voltage range, a step S302 ofdetermining whether or not the temperature of the OBC 200 has reached acorrected temperature range higher than the operating temperature rangeis performed. Afterwards, when the temperature of the OBC 200 hasreached the corrected temperature range higher than the operatingtemperature range, a step S304 of operating the water pump 320 at acorrected speed slower than the operating speed is performed. Asdescribed above, when the voltage of the high-voltage battery is withinthe reference voltage range, the amount of heat generated by the OBC 200is also reduced. The operation of reducing the frequency of operationand the intensity of cooling of the water pump minimizes the amount ofpower consumed by the unnecessary excessive operation of the water pump,thereby improving the efficiency of charging.

In addition, after the voltage of the high-voltage battery is measuredthrough the measuring step S100 and the step of comparing the voltage ofthe high-voltage battery with the previously-set reference voltagerange, when the voltage of the high-voltage battery is lower than thereference voltage range, a step S206 of determining whether or not thetemperature of the OBC has reached the previously-stored operatingtemperature range is performed in the rapid cooling step S200. Here,when the temperature of the OBC 200 has reached the previously-storedoperating temperature range, a step S208 of operating the radiator fan340 is performed, in which the operating power of the radiator fan isvaried depending on the temperature of the OBC.

In the safe cooling step S300, when the voltage of the high-voltagebattery is within the reference voltage range, a step S306 ofdetermining whether or not the temperature of the OBC has reached thecorrected temperature range higher than the operating temperature rangeis performed. Through this operation, the radiator fan is controlled tooperate when the temperature of the OBC is within the correctedtemperature range, and at this time, the operating power of the radiatorfan is varied depending on the temperature of the OBC.

According to the system and method for charging a plug-in hybrid vehicleas set forth above, when the OBC is cooled by circulating coolant withincreases in the temperature of the OBC during the charging of thebattery, the frequency and/or intensity of operation of the cooler 300is adjusted to improve the efficiency of charging.

That is, the operations of the water pump and the radiator fan arecontrolled by determining whether the voltage of the high-voltagebattery is within or out of the reference voltage range in which theon-board charging of the high-voltage battery is performed. Thisconsequently prevents power from being unnecessarily consumed by to theoperation of the cooler, such that the efficiency of charging isimproved and the OBC is properly cooled.

Although a preferred embodiment of the present invention has beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the presentinvention as disclosed in the accompanying claims.

What is claimed is:
 1. A system for charging a plug-in hybrid vehicle,the system comprising: a cooler configured to cool an on-board chargerby circulating coolant therethrough, the on-board charger charging ahigh-voltage battery of a vehicle; and a controller having voltageinformation of the high-voltage battery input thereto and a referencevoltage range previously stored therein, wherein when a voltage of thehigh-voltage battery is within the reference voltage range, thecontroller decreases a frequency of operation and an intensity ofcooling of the cooler, and when the voltage of the high-voltage batteryis out of the reference voltage range, the controller increases thefrequency of operation and the intensity of cooling of the cooler. 2.The system according to claim 1, wherein the cooler comprises a waterpump configured to cause a cooling medium to circulate when the on-boardcharger is required to be cooled.
 3. The system according to claim 2,wherein when the voltage of the high-voltage battery is lower than thereference voltage range, the controller controls the water pump tooperate when a temperature of the on-board charger has reached anoperating temperature range that is previously-stored.
 4. The systemaccording to claim 3, wherein when the voltage of the high-voltagebattery is within the reference voltage range, the controller controlsthe water pump to operate in a corrected temperature range higher thanthe operating temperature range.
 5. The system according to claim 2,wherein when the voltage of the high-voltage battery is lower than thereference voltage range, the controller controls the water pump tooperate at an operating speed that is previously stored.
 6. The systemaccording to claim 5, wherein when the voltage of the high-voltagebattery is within the reference voltage range, the controller controlsthe water pump to operate in a corrected temperature range lower thanthe operating temperature range.
 7. The system according to claim 1,wherein the cooler comprises a radiator fan configured to adjust atemperature of a cooling medium that circulates to cool the on-boardcharger.
 8. The system according to claim 7, wherein when the voltage ofthe high-voltage battery is lower than the reference voltage range, thecontroller controls the radiator fan to operate when a temperature ofthe on-board charger has reached an operating temperature range that ispreviously stored.
 9. The system according to claim 8, wherein when thevoltage of the high-voltage battery is within the reference voltagerange, the controller controls the radiator fan to operate in acorrected temperature range higher than the operating temperature range.10. The system according to claim 7, wherein the controller controls theradiator fan to operate at a higher intensity of operation withincreases in temperature in the operating temperature range or thecorrected temperature range.
 11. A method of charging a plug-in vehicle,the method comprising: measuring, by a controller, a voltage of ahigh-voltage battery; increasing, by the controller, a frequency ofoperation and an intensity of cooling of a cooler when the voltage ofthe high-voltage battery is out of a reference voltage range that ispreviously stored after measuring the voltage of the high-voltagebattery; and reducing, by the controller, the frequency of operation andthe intensity of cooling of the cooler when the voltage of thehigh-voltage battery is within the reference voltage range that ispreviously stored after measuring the voltage of the high-voltagebattery.
 12. The method according to claim 11, wherein: the coolercomprises a water pump configured to cause a cooling medium to circulatewhen an on-board charger is required to be cooled and a radiator fanconfigured to adjust a temperature of the cooling medium that circulatesto cool the on-board charger, and in increasing the frequency ofoperation and the intensity of cooling and reducing the frequency ofoperation and the intensity of cooling, an operating temperature rangeand an intensity of operation of the water pump and the radiator fan areable to vary depending on the voltage of the high-voltage battery. 13.The method according to claim 12, wherein in increasing the frequency ofoperation and the intensity of cooling, when the voltage of thehigh-voltage battery is lower than the reference voltage range, thewater pump is controlled to operate at an operating speed that ispreviously stored when a temperature of the on-board charger has reachedthe operating speed.
 14. The method according to claim 13, wherein inreducing the frequency of operation and the intensity of cooling, whenthe voltage of the high-voltage battery is within the reference voltagerange, the water pump is controlled to operate in a correctedtemperature range higher than the operating temperature range when atemperature of the on-board charger has reached the operating speed. 15.The method according to claim 12, wherein in increasing the frequency ofoperation and the intensity of cooling, when the voltage of thehigh-voltage battery is lower than the reference voltage range, theradiator fan is controlled to operate when a temperature of the on-boardcharger has reached the operating temperature range.
 16. The methodaccording to claim 15, wherein in reducing the frequency of operationand the intensity of cooling, when the voltage of the high-voltagebattery is within the reference voltage range, the radiator fan iscontrolled to operate in a corrected temperature range higher than theoperating temperature range.
 17. A non-transitory computer readablemedium containing program instructions executed by a processor, thecomputer readable medium comprising: program instructions that measure avoltage of a high-voltage battery; program instructions that increase afrequency of operation and an intensity of cooling of a cooler when thevoltage of the high-voltage battery is out of a reference voltage rangethat is previously stored after measuring the voltage of thehigh-voltage battery; and program instructions that reduce the frequencyof operation and the intensity of cooling of the cooler when the voltageof the high-voltage battery is within the reference voltage range thatis previously stored after measuring the voltage of the high-voltagebattery.